Trivalent metal-doped hexagonal plate-shaped zinc oxide and method for producing same

Abstract

The present invention provides zinc oxide having excellent infrared blocking ability, high whiteness, and excellent texture during use. The present invention relates to trivalent metal-doped hexagonal plate-shaped zinc oxide having an aspect ratio of 2.5 or greater, the trivalent metal-doped hexagonal plate-shaped zinc oxide having a trivalent metal element content based on the zinc element of 0.15 to 5 mol %, a whiteness of 90 or higher, and a powder spectral reflectance at a wavelength of 1500 nm of 80% or less.

The invention claimed is: 
     
       1. Trivalent metal-doped hexagonal plate-shaped zinc oxide, having an aspect ratio of 2.5 or greater, the trivalent metal-doped hexagonal plate-shaped zinc oxide having a trivalent metal element content based on a zinc element of 0.15 to 5 mol %, a whiteness of 90 or higher, and a powder spectral reflectance at a wavelength of 1500 nm of 80% or less. 
     
     
       2. The trivalent metal-doped hexagonal plate-shaped zinc oxide according to  claim 1 ,
 wherein the trivalent metal is at least one selected from the group consisting of aluminum, gallium, and indium. 
 
     
     
       3. The trivalent metal-doped hexagonal plate-shaped zinc oxide according to  claim 1 , wherein the trivalent metal-doped hexagonal plate-shaped zinc oxide has a median size of 0.05 to 5 μm. 
     
     
       4. The trivalent metal-doped hexagonal plate-shaped zinc oxide according to  claim 1 , wherein the trivalent metal-doped hexagonal plate-shaped zinc oxide has a median diameter of 0.08 to 5 μm. 
     
     
       5. The trivalent metal-doped hexagonal plate-shaped zinc oxide according to  claim 1 , wherein the trivalent metal-doped hexagonal plate-shaped zinc oxide has a median diameter of 0.71 to 5 μm. 
     
     
       6. The trivalent metal-doped hexagonal plate-shaped zinc oxide according to  claim 1 , wherein the trivalent metal-doped hexagonal plate-shaped zinc oxide has a ratio D90/D10 of 2.5 or less. 
     
     
       7. The trivalent metal-doped hexagonal plate-shaped zinc oxide according to  claim 1 , wherein the aspect ratio is determined by using a scanning electron microscope that produces micrographs at 2000× to 50,000× magnifications, and the aspect ratio is determined as a ratio of L/T,
 wherein L is an average of measured particle diameters of 100 hexagonal plate-shaped zinc oxide particles, each of the particle diameters being a diagonal diameter of a frontal image of a hexagonal plate-shaped surface of a hexagonal plate-shaped zinc oxide particle, and 
 T is an average of measured thicknesses of the 100 hexagonal plate-shaped zinc oxide particles, each of the thicknesses being a shorter length of the frontal image of a side face of the hexagonal plate-shaped zinc oxide particle.